SHANGHAI, July 29 -- Aluminum Corp. of China Ltd., the nation's biggest producer of the metal, suspended its shares from trading ahead of a signing ceremony today in Beijing that will be attended by Rio Tinto Group.

Aluminum Corp.'s parent company, known as Chinalco, announced the event without giving details of the agreement. Rio will attend the ceremony starting at 3:30 p.m. local time, according to an invitation seen by Bloomberg News.

Chinalco in March signed a non-binding accord to pay $1.35 billion for a stake in Rio Tinto's Simandou iron ore project in Guinea. The state-owned company is "watching closely" for opportunities to invest in other projects abroad, including Oyu Tolgoi, a Mongolian copper venture between Rio and Ivanhoe Mines Ltd., Xiong Weiping, chairman of both Chinalco and Chalco, as publicly traded Aluminum Corp. is known, said on March 29.

Chalco and Rio will sign an agreement for the development of a large iron-ore mine in Guinea, the Shanghai Securities News reported, without saying where it got the information.

Chinalco would fund the purchase of a 44.65 percent stake in Simandou, described by Rio as the world's "top" undeveloped iron-ore deposit, by financing development over the next two to three years, London-based Rio said March 19. Simandou has 2.25 billion metric tons of iron ore resources, Rio said on March 15.

Rio stated in March it had spent $600 million on exploration and development of Simandou after saying in 2007 that it may invest at least $6 billion.

Rio is working to repair relations with Chinalco, its largest shareholder, which were soured last year when Rio scrapped a $19.5 billion investment by the Chinese company and four Rio employees were arrested in Shanghai.

Chalco's shares are expected to resume trading in Hong Kong and Shanghai on July 30, the Beijing-based company said in a statement. Rio rose 0.3 percent to A$71.23 at 10:45 a.m. in Sydney. David Luff, a Rio spokesman based in Melbourne, declined to comment. Yuan Li, head of communications with Chinalco, also declined to comment on the signing ceremony.

SHANGHAI, July 29 -- Aluminum Corp. of China Ltd., the nation's biggest producer of the metal, suspended its shares from trading ahead of a signing ceremony today in Beijing that will be attended by Rio Tinto Group.

Aluminum Corp.'s parent company, known as Chinalco, announced the event without giving details of the agreement. Rio will attend the ceremony starting at 3:30 p.m. local time, according to an invitation seen by Bloomberg News.

Chinalco in March signed a non-binding accord to pay $1.35 billion for a stake in Rio Tinto's Simandou iron ore project in Guinea. The state-owned company is "watching closely" for opportunities to invest in other projects abroad, including Oyu Tolgoi, a Mongolian copper venture between Rio and Ivanhoe Mines Ltd., Xiong Weiping, chairman of both Chinalco and Chalco, as publicly traded Aluminum Corp. is known, said on March 29.

Chalco and Rio will sign an agreement for the development of a large iron-ore mine in Guinea, the Shanghai Securities News reported, without saying where it got the information.

Chinalco would fund the purchase of a 44.65 percent stake in Simandou, described by Rio as the world's "top" undeveloped iron-ore deposit, by financing development over the next two to three years, London-based Rio said March 19. Simandou has 2.25 billion metric tons of iron ore resources, Rio said on March 15.

Rio stated in March it had spent $600 million on exploration and development of Simandou after saying in 2007 that it may invest at least $6 billion.

Rio is working to repair relations with Chinalco, its largest shareholder, which were soured last year when Rio scrapped a $19.5 billion investment by the Chinese company and four Rio employees were arrested in Shanghai.

Chalco's shares are expected to resume trading in Hong Kong and Shanghai on July 30, the Beijing-based company said in a statement. Rio rose 0.3 percent to A$71.23 at 10:45 a.m. in Sydney. David Luff, a Rio spokesman based in Melbourne, declined to comment. Yuan Li, head of communications with Chinalco, also declined to comment on the signing ceremony.